Grinding machine



` Feb.25,1941. AHA-RRQ@ y 2,233,312

GRINDING MACHINE Patented Feb. 25, 1941 UNITED STATES 2,233,312 GammoMACHINE James A. Harrold, Clifton, N. J., assirnor of one- 'l half toHerman Pollack, Paterson, N. J.

Application August 23, 1939, serial No. 291,589

This invention relates to an improvement in lens edge grinding machines.I

An object of this invention is to intermittently rotate theV lens beingground and such rotary vl movement being imparted to the lens upon the lremoval of the glass down to size governed by a pattern. Thisconstruction diiering from the present or generally accepted method forgrinding lens wherein the lens and grinding wheel are both continuouslyrotating during the operation of grinding the lens down to size orshape.

In the present invention, the lens is held in contact with acontinuously rotating grinding wheel until a desired amount of glass orma- ]5 terial is removed whereupon the lens is rotated suilciently topresent another surface to the wheel, and so on until the lens has beengiven a complete rotation in producing the desired shaped lens. Apattern is provided for governing the 20 amount of material to beremoved. As each quantity of material is removed from the stationarylens, the pattern will be moved into ay position for establishing acircuit whereupon suitable mechanism will be actuated for causing geartrains to be operated for rotating the lens a sufli- Acient amount tobring a new surface in contact with the grinding wheel whereupon thecircuit will be broken and the gear train stopped and a further grindingoperation on the lens performed 30 by the grinding wheel.

The invention consists further in novel driving means for impartingintermittent motion to the carriage supporting the lens and pattern sothat upon the removal of a portion of the glass 35 or material,composing the lens or other article,

is removed from the stationary lens held and supported by the carriage,the driving mechanism will be operated for imparting a slight rotarymovement to the lens to bring a new surface into y 40 contact with thegrinding Wheel, and upon the bringing of this new surface into contactwith the grinding wheel, the'driving mechanism will be discontinued andthe material of the lens removed, and upon the completion of this grind-45 ing operation the driving mechanism will be again established andanother cycle completed. In this manner a complete rotation of the lenswill proand it is necessary to disengage the carriage and stop therotation of the lens and for the operator to determine by hand, that isby"'feel, whether or not the lens has been ground to the proper shapeand size and then causing the lens to be 5 again brought into engagement`with the grinding wheel for removing these rough or high spots thatexist on the lens before it can be termed a iinished product. Whereas,with this invention, these objections are eliminated and upon onecomplete revolution or in some instances one additional turn at aregular speed would assure a smooth edge and the lens would be completedat onethird the usual time now required without the necessity of beingobserved by an attendant to insure that all uniinished portions or highspots have been removed from the lens.

The invention consists of certain novel features of construction andcombinations of parts which will be hereinafter described and pointedout in the claims.

In the accompanying drawings,

Figure 1 is a detailed view partly in section of the automatic means orcontrol for governing ythe rotation ofthe lens to be ground.

Figures 2 and 3 are horizontal sectional views of the clutch mechanismshown in Figure 1. Figure 4 is a perspective view of a standard lensgrinding machine having a portion broken away l to better show theinvention applied thereto.

Figure 5 is a View in side elevation oi a portion of such standardmachines showing some of the parts broken away to illustrate the drivingmechanism for the lens supporting carriage.

Figure 6 is a detailed view in elevation show- 35 ing the positionassumed by the lens and pattern during .the grinding operation of thepresent invention.

This invention is capable of being applied and used in conjunction withthe standard machines and for the purposes of illustration the inventionhas been adapted to a rimless edge grinder.

A portion of such machine as is believed sufficient for illustration hasbeen disclosed -in the drawings and will now be described for thepurpose of obtaining an understanding of the present invention.

Referring to Figures 4 and 5, the numeral 35 represents the machine baseor bed upon which is mounted for reciprocatory movement a table 5|. Anarbor 36 is mounted in suitable bearings 31 on the base 35. Power istransmitted to the arbor 36 through a pulley 38 mounted thereon and abelt 39 transversing the pulley, which' belt is connected to somesuitable power supply, not

shown. Mounted on the arbor 38 is a grinding wheel or stone 48.

Table 5| is provided with two stanchions 52. Interposed between thestanchions and supported thereon for oscillation is a carriageconsisting of housings 56 and 51 connected together by a tubular member55, the housings 56 and 51 being connected by pivots or trunnions 53-54to the stanchions. 52. .Journalled in the tubular member is a shaft 68provided with gears -1|, 12 at each end which are located within thehousing 56, 51 respectively. A head spindle 11 is journalled in thehousing 56 and is provided with a gear 15 which meshes with an idlergear 13 journalled in the housing and which idler gear meshes with thegear 1| of the shaft 68 whereby motion is imparted from the shaft 88 tothe spindle 11. A tail spindle 18 is journalled in the housing 51 and isprovided with a gear 16 which meshes with an idler gear 14 journalled inthe housing 51 and which idler gear meshes with the gear 12 of the shaft68 for imparting rotation from the shaft 68 to the tail spindle 18. Thehead spindle 11 and the tail spindle 18 are provided respectively withpad holders 80, 8| for supporting the lens material 82 to be ground. Thehead spindle 11 also carries a pattern 19 which will be g of a size andshape that conforms to the shape and size of the lens to be ground.Within the housing 51 is a yoke 89 which engages a collar 98 on spindle9| mounted for reclprocation in the housing. Interposed between thespindle 9| and the shaft 18 is a thrust bearing 92. A lever extendsthrough and is mounted on the housing 51 and is provided with. a cam 88for actuating the yoke 89 for causing the pad 8| to be moved toward thepad for clamping the lens between the two pads of the shafts 11, 18. Themovement of the lever 83 in one direction will cause the spindle 9| toexert pressure on the shaft 18 for reciprocating it for either clampingthe lens in position between the pads 80, 8| or for releasing the lensfrom engagement with the pads.

A pulley 4| is mounted on a shaft 42 Journalled in the base 35 and poweris transmitted to the pulley 4| from a pulley 48 on the arbor 36 througha belt 43. Motion from the shaft 42 is transmitted through the worm gear44 thereof through a universal connection 45 to shaft I. Gear housing 61is mounted on one of the stanchions 52 and has a shaft 65 journalledtherein. The shaft is connected by means of a compensating means 10 witha disk 69 on shaft 68. The shaft 65 is provided with a helical gear 66adapted to mesh with a helical gear 59 on shaft 58. Shaft 58 isjournalled in a bearing bracket 68 which is pivoted to the stanchion 52by means of a shaft 6I. A bracket 63 connected to` the gear housing 61supports a cam shaft 62 which is adapted to be oscillated by means ofthe handle 62' for oscillating the bracket 60 in establishing engagementbetween the gears 59 and 66. When these gears are out of engagement, thehand wheel 64 on the shaft 65 permits manual operation of the gear train1|, 13, 15 and 12, 14, 16 for manually turning the lens and pattern.

Shaft 58 is connected to shaft 2 by means of a universal connection 58and shaft 2 is arranged in alignment with shaft I, which shafts arecapable of being engaged and disengaged through suitable clutchmechanism whereby intermittent motion may be impartedfrom the shaft 2 tothe shaft 68 and gear trains.

The foregoing description is primarily based on the standard machine,and hence forms no part of this invention except insofar as thev drivemechanism is concerned with particular respect'- to shafts I and 2 andits related mechanism to now be set forth.

engaging the collar I2 and the other end xed to the sleeve 5 so thatupon the rotation of the shaft I, the collar I2, sleeve 5 and clutchring 3 all rotate as a unit.

Mounted on the lower end of shaft 2 is a sleeve or outer clutch member 6which has a sliding engagement upon the shaft 2 through a key I6 carriedby the shaft and a keyway or groove I1 formed in the sleeve. The lowerend of the sleeve 6 is provided with a clutch ring 4 having an outwardlyand downwardly tapering surface which is adapted to engage the balls 96for retaining them in the cage. The balls 96 travel on the inner surfaceof the clutch ring 4 and ride in recesses I3 formed in the outer face ofthe clutch ring 3 on the shaft I. When power is desired to drive theshaft 2 and shaft I is rotating, the .balls 96 will be caused to travelin the recesses I3 where they will be impinged against the walls of therecesses and the inner f ace of the ring 4 for locking the clutchmembers together whereby the motion of shaft I will be imparted to shaft2, Figure 3. Upon the raising or moving of the sleeve 6 upwardly, thepressure on the balls is released and the tension of the spring 1 isreleased causing the balls to -be moved to the position as indicated inFigure `2 or in free running position.

Loosely mounted on shaft I is a sleeve 9 which is supported thereon bythe collars I2 and I4 xedly secured to the shaft I. the sleeve 9 aretwoA parallel plates 2| provided with slots 34 fitting around the'sleeve9. lThese plates are clamped together and about the sleeve '9 by meansof clamping bolt 23 and their outer ends are connected together bly atransverse clamp bolt 24 similar to the -bolt 23. Connected to theplates are stanchions 26 by means of the bolt 24 and dowels 25.Pivotally connected to the stanchions are two parallel rods 21'hingedthereto by means of a pin 28. 'I'he other terminals of the rods 21 areconnected to a trunnion collar l0 carried by the sleeve 6 o r outerclutch member, this collar I0 being held to the sleeve by means of acollar II. Mounted on the plates 2| is a cross plate 22 for supportingthe magnet I8 by means of brackets 3| for the energizingcoil I9. Anarmature 28 is connected to'the rods or levers .21 by means of brackets29. Magnet coil terminals 33 are mounted upon an insulated strip A32carried by the plates 2| and suitably connected to the magnets I8.

The wires IIiIl-IiiI of the circuit lead from a suitable source througha transformer, rectifier.

The electrical circuit consisting of the wires |00|||I extending fromthe contacts 33'to the seat 84, is provided with a suitable transformer,rectifier and condenser. j

The sizer seat 84 is carried by an arm |82 connected to the hand wheel85 which is supported massigv on' the base 6I. Suitable insulation |88is interposedV between the seat 84 and arm |02.V The electric 'circuitfromV the terminals 88 extends to the sizer seat 84. one wire beingconnected to the seat 84 and the other wire to arm |82. The circuit isgroundedon the machine as indicated at .I 84. The sizer seat 84 ismounted upon the table I and is capable of adjustment with respect tothe pattern or former 18 on the shaft 11 so that as the former makescontact with the sizer seat 84, the electric circuit is establishedcausing the magnet I8 to be energized and attracting the armaturethereto. The movement of thearmature 20 into engagement with the magnetoscillates the rods 21 causing the trunnion collar I8 to force the outerclutch member 8 on the shaft 2 downwardly against the tension of thespring V8, interposed between the collar and end of shaft I, forestablishing an engagement between the two shafts.

The axial movement of the outer clutch member 6 into engagement with theinner clutch member causes an engagement between the downwardly taperingsurface on the inner face of the clutch member 4 and the balls 88carried-by the cage 5, forcing the balls inwardly against the clutchring 3 and causing them to roll across the circular recesses I8 againstthe pressure exerted by the spring 1 and wedging the balls between therings Band 4 in a positive grip, as indicated in Figure 3. The shaft Iwhich is rotating through its connection with the arbor 36, lpulleys 40,4I andI belt 48, will now transmit this rotary movement to shaft 2through the outer clutch member 6 which is keyed thereto. Therotation ofshaft 2 will be transmitted to the gear 59 which is in mesh with helicalgear 88 and the rotation of the gear 66 will cause power to betransmitted to shaft 65through the compensating connection 68, 18 toshaft 68 of lthe carriage. The rotation of shaft 68 will` cause thegears 1l, 12 thereon to be rotated and motion will be imparted therefromto the gears 13, 14. This movement will be imparted to the lens 82 andformer 18 causingv them to be rotated as clearly indicated in Figure 6.As soon as the lens 82 has been rotated sufficiently to again contactwith the grinding wheel 46 andbringing a new surface tothe grindingwheel to be ground, the former 19 will have passed out of engagementwith the sizer seat 84 thereby breaking the electric circuit andallowing the armature 28 lto become disengaged from the magnet and theouter clutch member 6 to move axially under the influence of the spring8 away from the inner clutch member thereby declutching the shaft 2 fromthe shaft I and interrupting .the rotation of the shaft 2, 68, 11 and18.

f When outer clutch member 6 is moved axially inward or downwardadditional pressure is placed on balls due to the tapering form of outerclutch member 4. As shaft I is turning carrying 8 and 6 this additionalpressure 'due to the lay of 8, causes balls 96 .to roll across circularrecesses I3 carrying cage 5 with them, which is normally held inposition shown in Figure 2 by spring 1, to the position shown in Figure3, the engaged position. 'I'here are three sequences of action here thatmust be explained. Note Figure 2, balls 88 and ball cage 5 are held byspring 1 in a positionv change in position of balls 86 in ,recesses I8,and under no circumstances must balls be permitted to leave theirrespective recesses. The drag is between balls tending to mount thesides of recesses due to action of spring 1 but being prevented, byouter clutch member 4 as I. 8 and 6 turn and member 4 is stationary. Asmember 4 is moved inward or downward additional pressure is placed onballs due to taper of inner surface of member 4, the balls 88 then tendto roll down to center of recesses at which point magnet I8 has drawnarmature 28 into full contact and exerts its greatest pull, balls mustcontinue to roll until they are wedged between the opposite sides ofrecesses and outer clutch member 4 as Figure 3.

. As long as this downward pressure continues the clutch is engaged anddriving its load. When the magnet releases it is to be noted thattapered inner surface of clutch member 4 tends to rise as pressure isreleased and spring 1 tends to return balls to their original position,see Figure 2. The clutch is engaged or operated without friction betweenouter clutch member 4, inner clutch member 3 and balls. Asclutch closeson balls there is no friction as balls are free to roll and they do rolluntil stopped solid as they wedge between members 3 and 4.

As the carriage is pivotally supported upon the stanchions 62 by thetrunnions 53, 54, this carriage is capable of oscillating to and fromthe grinding wheel 46 although it normally hangs substantially in avertical position and "as the lens during the grinding operation is heldagainst rotation by the stationary gear trains against the face of thegrinding wheel, the weight of the carriage and the tendency for thecarriage to move toward the grinding wheel holds the lens in positionagainst the face of the grinding wheel. To insure of the lens being heldagainst the face of the grinding wheel, a bracket 48 is connected to thehousing 51 of the carriage, upon which is mounted a weight 48 adjustablysupported on a rod 58 of the bracket 48. By positioning the weight 48along the rod 58, it'can be readily determined the amount of pressurerequired for insuring the lens being held against the face of thegrinding wheel 46 to obtain the desired cutting action. Naturally as thelens is ground down to size or to the shape desired, .there will begreater oscillation of the carriage as the former 19 contacts with'theseat 84.

The driving connection between shaft 2 and 68 may be disconnectedwhenever desired by simply operating -the handle 62' causing the c-amshaft 62 to osclllate the bracket 60 and causing the gear 58 to be movedout of engagement with the gear 86 whereupon 4the sli-aft 68 can berotated `by means of the hand wheel 6-4 and through the train of gearing13, 15, 14, 18, the lens 82 and pattern 18 may be adjusted or examined-to suit the wishes of the operator.

In .the operation of grinding the lens, which has been fabricated asprescribed by an optician, the proper pattern or former 18 is selectedand mounted on the head spindle 11, and then the lens is clamped betweenthe pads 88, 8 I, by shifting the spindle 18 vthrough the lever 83, cam88 and yoke 88. Sizer hand wheel 85 is operated for setting the sizerseat 84 with respect to the former 18. The carri-age which may beelevated or swung by the handle 86 is now lowered allowing 'the lens torest against the grinding wheel 46. During the preliminary assembly ofthe parts the gears 58v and y88 are generally out of mesh permitting thespindles 11, 18 of the carriage :to be operated through the hand wheel64. However.

` as soon as the grinding operation is to be effected,

the gears 59 and 88 are brought into engagement.

Upon .the rotation of the grinding wheel 48 and setting the lens againstthe wheel 48, the lens will be grounded until the sizer seat 84 andpattern 19 contacts.

The carriage is being moved to the vertical due to the removal of thematerial from the lens and causing the pattern 18 to be brought closerand closer'to the sizer seat, and upon the removal of the necessaryquantity of material from the lens to conform to the shape of thepattern, the pattern will be brought into engagement with the sizer seat84 and there wilibe no further grinding contact between the lens andgrinding wheel. When the seat 84 and pattern 19 contacts, see Figure 6,an electric circuit is established, through the circuit between the seatand the magnet I8..

The energization of the magnet I8 causes .the armature 20 to beattracted and brought into engagement therewith, .this action causes therods or levers 21 to be oscillatedon their pivot 28. The levers 21 willcause 4the outer clutch member 9 to be' moved axially of .the shaft 2,bringing thel slight drag of the balls 95 against the outer clutch ring4 of the clutch member 8, but not sufficient to cause rthe clutchmembers to be engaged until .the clutch member 8 is moved axially underthe influence of the levers 21, .to-bring it into a posiltion -to causeIthe balls 98 to be moved inwardly into the recesses I8 of the ring 8.This movement of member 9, due to the rotation of shaft I and cage5 willcause the fballs 8 to ride across the recesses I2 'and exert a pressurebetween .the rings 8 and 4 sufcient to lock the two clutch memberstogether. whereupon motion is imparted to shaft 2 causing it to rotategears 59, 66 and shaft 88. The rotation of shaft 68 will .transmitmotion to the spindles 11-18 through the gear trains and thereby causethe lens 82 and former 18 to be rotated for the purpose of bringing anew surface of the lens into engagement with .the

grinding wheel. It is 4to be noted that when coni tact is made betweenpattern 19 and sizer seat 84 the lens isvout of contact with Ithegrinding wheel and no further amount of glass is being removedtherefrom.

Referring to Figure 6, the lens 82 is shown with several of itsperipheral faces completed or ground f to conform to the pattern 19,while the face against the wheel 48 is being ground and partiallyfinished. The lower faces are still unground.

' This can be readily appreciated as the pattern and lens are rotated inaclockwise direction to bringnew surfaces into contact with -thegrinding wheel. The sizer seat 84 has its outer face inv the presen-tinstance curved substantially to the curvature of the grinding wheel 48,and it is val of contact of the lens with .the grinding wheel and theinterval of contact of the pattern with .the seat 84. Thait is, the lensis ground duringthe period that contact is' broken between Ithe pattern19 and seat 84 and until contact is again established between thesemembers 19 and 84. Therefore, there will be numerous engagements anddisengagements between the seat 84 and pattern 19, in grinding each faceof the lens, or such faces as correspond to .the faces of `the pattern19.

The entire face is not removed at each engagement between the lens 82and grinding wheel, but instead only a small portion, 'or so much of.the lens as can be presented .to the annular face o1' the grindingwheel. As a result. there will be numerous engagements between the'pattern and seat for stopping 4the grinding operation, because the lenswill be out of contact with the Wheel' I when the pattern engages theseat 84. Of course. this engagement of .the pattern with the seatestablishes the circuit, and power is .transmitted to the spindles 11-18causing the pattern 19 and lens 82 -to'be rotated, but only sufficientto bring a portion of .the lens into engagement with the grinding wheeland the pattern out of contact the circuit andthe rotation ofthespindles 11, 18,

of the carriage, the lens 82 and former 19 are now rotated to bring anew surface of the lens into engagement with the grinding wheel,.thereby elevating the carriage and causing Ithe contact between thepattern 19 and seat 84 to be broken. Substantially one or two.thousandths of an inch movement of the pattern 19 away from the seatwill break the circuit and allow the magnet I8l -to release the armature20. The outer clutch member l5 will now automatically move axially awayfrom the inner'clutch member by the combined action of spring 8 and thewedge formation on the inner surface of outer clutch ring 4 due to thetendency of the spring 1 to return the balls 96 of the cage 5 to theopposite side of the circular recess I3 as indicated in Figure 2. Thepressure on the balls is relieved upon the movement of the outer clutchmember away therefrom and therefore the clutch members. are releasedfrom engagement with each other and the balls and cage 5 are againreturned to free running position as indicated in Figure 2.

disengaged through a one way or over-running clutch, insuringpractically an instantaneous engagement and disengagement of the shafts,without causing the spindles 11 and 18 to' be overdriven in advancingthe lens blank in contact with the grinding wheel, but only causing amovement of the blank suilicient to present a new surface to thegrinding wheel. When the clutch is disengaged, and the pressure onmember 6 is relieved by the magnet, the balls 96 are in the positionindicated in Fig. 2, there is a slight drag as the cage 5 turns and'ring member 4 is stationary. This prevents any backing up of the spindlegear train due to any friction'between grinding wheel and lens blank,when lens blank is first set against grinding wheel. This drag isinsufilcient to turn gear train and spindle and tail spindles and havinga slidable clutch ele-- 55 posed between said clutch elementsl of saiddriven n assembly even when lens blank is'raised off of grinding wheel.

The lens is now again held stationarily in contact with the grindingwheel as the gear trains will act as a-brake against the rotation o fthe spindles I1 and 1l. This cycle of operation is continued until allof the material of the lens has been removed in conformity with theshape desired by the pattern employed. One complete turn or revolutionof the lens is suilicient generally to remove all of the glass and bringthe lens downto proper size and shape. Of urse. as the last amount ofglass is removed the pattern and seat will again contact and the circuitwill be established causing the clutch to lbe engaged between shafts land 2 so that the spindles 11, Il are again rotated and will cause thelens to be rotated. This rotation of the lens along with the rotation ofthe grinding wheel insures the removal of any'superiiuous glass that mayaffect a true shape or size of the lens. One revolution of the lensunder this condition is Agenerally sumcient. Oi course. if there are anyhish spots left on the lens after the first revolution, the lens willcontact with the grinding wheel and raise the carriage and break thecircuit sothat the lens will dwell or stop at this high spot until thismaterial has been removed when the lens will immediately begin torotate. The continuous.

turning or rotation of the Alens with respect to the grinding wheelindicates to the operator that the lens is completed. With this methodof removing the material and the forming of a lens production time isreduced from one half to one third compared with the general methods ofthepresent time. This method entirely eliminates the constant stoppingof the machine or carriage where the lens is continuously driven for theoperator to examine the lens by feel to determine whether a suilicientamount of lens has. been removed.

What I claim is: l. In a lens grinding machine having a continuouslydriven grinding wheel and intermittently rotated head and tail spindles.said head and tail spindles supporting a pattern and a lens blank to beoperated upon by said grinding heel, means including a continuouslyrotative ving shaft and a driven shaft for imparting rotary movement tosaid spindles and lens blank, said driven shaft drivably connected tosaid head ment connected thereto, a clutch element xed on said driveshaft, spring controlled ball means loosely mounted on saiddrive shaftand interanddrlve snaftsandnormallymaintainingsaid clutch elementsdeclutched, electro-magnetic means for exerting pressure on saidslidable clutch element of said driven shaft for forcing it intoengagement with said means and the other able clutch element whereuponsaid ball means will automatically cause the clutch .eiements to bedeclutched and interrupting the movement of said lens blank.

2. In a lens grinding machine having a continuously u'riven grindingwheel and intermittently rotated head and tail spindles, said head andtail spindles supporting a pattern anda lens blank to be operated uponby said grinding wheel, means including a continuously rotative drivingshaft and a driven shaft for imparting rotary movement to said spindlesand lens'blank, said driven shaft drivably connected to said head andtail spindles and having a slidable clutch element connected thereto, aclutch element fixed on said driving shaft, spring controlled ball meansloosely mounted on said driving shaft and interposed between said clutchelements of said driven and drive shafts and normally maintaining saidclutch elements declutched, electromagnetic means for operating saidmovable clutch element, an electric circuit associated with saidmagnetic means, contact means in said circuit adapted to beintermittently engaged by said pattern for causing the magnetic means tobe energized and deenergised. said magnetic means upon being energizedexerting pressure on said movable clutch element for forcing it intoengagement with said ball means and the other clutch element for causingsaid clutch elements to be clutched and imparting rotary movement to thelens blank and pattern. said pattern upon rotation being disengaged fromsaid contact means and thereby breaking the circuit and deenergizingsaid magnetic means, said magnetic means upon being deenergizedrelieving the pressure on said clutch element whereupon said ball meanswill automatically cause the clutch elements to be declutched andinterrupting the movement of said lens blank and pattern.

JAMES A. HARROLD.

